1. Field of the Invention
The invention relates to a control device and a control method for a vehicle, and more particularly, to an art of making a further improvement in fuel economy while securing an amplification effect of a braking force at the time of brake operation in a vehicle that can coast, namely, travel (run) with an engine brake force made smaller than during engine brake travelling.
2. Description of Related Art
For engine brake travelling during which an engine and wheels are connected together and a vehicle runs with engine brake effectuated through driven rotation of the engine, with a view to making an improvement in fuel economy by prolonging the travel distance, coasting during which the vehicle runs with an engine brake force made smaller than during the engine brake travelling has been conceived. A device described in Japanese Patent Application Publication No. 2002-227885 (JP-A-2002-227885) is such an example. There have been proposed two control modes, namely, (a) first coasting during which the vehicle runs with the engine stopped from rotating and (b) second coasting during which the vehicle runs with the engine allowed to rotate. Specifically, first coasting is free-run coasting during which a clutch is released to disconnect the engine from the wheels and the supply of fuel to the engine is stopped so that the engine is stopped from rotating. Second coasting is neutral coasting during which the clutch is released to disconnect the engine from the wheels and fuel is supplied to the engine so that the engine is operated (autonomously rotated). Then, this first coasting and this second coasting are not distinguished from each other in particular, and one of them is executed under a certain condition.
By the way, in the aforementioned Japanese Patent Application Publication No. 2002-227885 (JP 2002-227885 A), if the operation amount of a brake pedal, namely, a brake requirement amount becomes equal to or larger than a predetermined value, the control mode of coasting is canceled without distinguishing the aforementioned two kinds of coasting from each other. That is, the operation of the brake pedal means a driver's requirement for deceleration. Therefore, if the brake requirement amount is large, coasting is cancelled to make a recovery to engine brake travelling during which a larger engine brake force is obtained. Besides, if the brake requirement amount is equal to or larger than a predetermined value as in this case, the control mode of coasting cannot be entered.